Meditation’s Reduction of Pain is Independent of Brain Opioid Systems
By John M. de Castro, Ph.D.
“Bit by bit, as I sat noticing my breath and body sensations, I began to feel the deep knots of pain in my body start to untie themselves.” – Avi Craimer
We all have to deal with pain. It’s inevitable, but hopefully it’s mild and short lived. For a wide swath of humanity, however, pain is a constant in their lives. At least 100 million adult Americans have chronic pain conditions. The most common treatment for chronic pain is drugs. These include over-the-counter analgesics and opioids. Opioids act on a system in the brain that contains receptors that respond to these drugs. But opioids are dangerous and highly addictive. Prescription opioid overdoses kill more than 14,000 people annually. So, there is a great need to find safe and effective ways to lower the psychological distress and improve the individual’s ability to cope with the pain.
Pain involves both physical and psychological issues. The stress, fear, and anxiety produced by pain tends to elicit responses that actually amplify the pain. So, reducing the emotional reactions to pain may be helpful in pain management. There is an accumulating volume of research findings to demonstrate that mind-body therapies have highly beneficial effects on the health and well-being of humans. Mindfulness practices have been shown to improve emotion regulation producing more adaptive and less maladaptive responses to emotions. Indeed, mindfulness practices are effective in treating pain in adults. It is not known whether meditations effects on pain are mediated by the same system that responds to opioids.
In today’s Research News article “Enhancement of Meditation Analgesia by Opioid Antagonist in Experienced Meditators.” (See summary below or view the full text of the study at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6162167/ ), May and colleagues recruited adult experienced meditators who were free of chronic pain and not taking opioid drugs. They were measured for pain responses to an electric shock delivered to the ring finger of the non-dominant hand. They rated the level of pain on a 10-point scale. The participants first rated pain under normal conditions and later while meditating. Those participants who demonstrated a 15% or more reduction in pain while meditating (meditation analgesia) participated in the second half of the experiment. Half the participants received a saline injection and half an injection of Naloxone (an opioid receptor blocker) and repeated the pain testing while meditating. In the next session the participants received either the saline or Naloxone injection that they did not receive in the first session. So, all participants received both saline and Naloxone injections and were tested for their pain sensitivity.
They found in the initial test that 85% of the participants demonstrated a 15% or more reduction in pain while meditating (meditation analgesia). This high rate suggests that meditation routinely produces a reduced experience of pain in experienced meditators. In the second phase they found that meditation analgesia was not only not reduced by Naloxone injection but actually significant increased, with larger reductions in both pain intensity and pain unpleasantness to the electric shock after Naloxone injection than after saline injections.
The opioid system of the brain is a well-established pain processing system. Its function is blocked by Naloxone. So, the reduction in pain produced by meditation was not affected by disrupting the opioid system. So, meditation analgesia must not be due to changes in this opioid system. It must be processed by a different system in the brain. The increase in meditation analgesia after Naloxone was a surprise, for which there is no viable explanation at this time. Hence, meditation reduces pain sensitivity and does so independent of the brain system that responds to opiates.
So, meditation reduces pain sensitivity independent of brain opioid systems.
“Mindfulness meditation is believed to be a viable alternative to drugs when it comes to pain management. Although research is still in the beginning phases, pilot studies focusing on the benefits of mindfulness have shown promising outcomes for patients suffering from chronic ailments such as fibromyalgia, back pain, migraines, etc.” – Mindworks
CMCS – Center for Mindfulness and Contemplative Studies
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May, L. M., Kosek, P., Zeidan, F., & Berkman, E. T. (2018). Enhancement of Meditation Analgesia by Opioid Antagonist in Experienced Meditators. Psychosomatic medicine, 80(9), 807-813.
Studies have consistently shown that long-term meditation practice is associated with reduced pain, but the neural mechanisms by which long-term meditation practice reduces pain remain unclear. This study tested endogenous opioid involvement in meditation analgesia associated with long-term meditation practice.
Electrical pain was induced with randomized, double-blind, cross-over administration of the opioid antagonist naloxone (0.15-mg/kg bolus dose, then 0.2-mg/kg per hour infusion dose) with 32 healthy, experienced meditation practitioners and a standardized open monitoring meditation.
Under saline, pain ratings were significantly lower during meditation (pain intensity: 6.41 ± 1.32; pain unpleasantness: 3.98 ± 2.17) than at baseline (pain intensity: 6.86 ±1.04, t(31) = 2.476, p = .019, Cohen’s d= 0.46; pain unpleasantness: 4.96 ±1.75, t(31) = 3.746, p = .001, Cohen’s d = 0.68), confirming the presence of meditation analgesia. Comparing saline and naloxone revealed significantly lower pain intensity (t(31) = 3.12, p = .004, d = 0.56), and pain unpleasantness (t(31) = 3.47, p = .002, d = 0.62), during meditation under naloxone (pain intensity: 5.53 ± 1.54; pain unpleasantness: 2.95 ± 1.88) than under saline (pain intensity: 6.41 ± 1.32; pain unpleasantness: 3.98 ± 2.17). Naloxone not only failed to eliminate meditation analgesia but also made meditation analgesia stronger.
Long-term meditation practice does not rely on endogenous opioids to reduce pain. Naloxone’s blockade of opioid receptors enhanced meditation analgesia; pain ratings during meditation were significantly lower under naloxone than under saline. Possible biological mechanisms by which naloxone-induced opioid receptor blockade enhances meditation analgesia are discussed.